Long regular expressions are hard to read.
A good practice is to use the x modifier and break the regex into multiple lines with comments explaining the parts.
But,
with the usual // delimiters,
the beginning and end can be hard to match,
especially in a s/// regexp.
Instead,
try using {} characters to delimit your expressions.

Compare these:

s/
<a \s+ href="([^"]+)">
(.*?)
</a>
/link=$1, text=$2/xms;

vs.

s{
<a \s+ href="([^"]+)">
(.*?)
</a>
}
{link=$1, text=$2}xms;

Is that an improvement? Marginally, but yes. The curly braces lead the eye better.